Hybrid electric vehicles have electric motors that are driven by high power solid state silicon transistors to switch power to the motors. Liquid cooling of power electronics allows for high levels of power dissipation by power electronics. However adding liquid cooling to a vehicle that uses a liquid suitable for direct cooling of the electronics (e.g. dielectric fluid) undesirably increases cost. Also adding complicated heat exchangers so heat from the electronics can be transferred to the already available engine coolant without exposing the electronics to the ionic contamination of engine coolant also undesirably increases cost. What is needed is a way to package power electronics so that the electronics can be directly exposed to readily available engine coolant.